LTC2435CGN Linear Technology, LTC2435CGN Datasheet - Page 26

• Manufacturer Part Number: LTC2435CGN
• Description: IC ADC DIFF I/REF 20BIT 16-SSOP
• Manufacturer: Linear Technology

Specifications of LTC2435CGN

• Number Of Bits: 20
• Sampling Rate (per Second): 15
• Data Interface: MICROWIRE™, Serial, SPI™
• Number Of Converters: 2
• Power Dissipation (max): 1mW
• Voltage Supply Source: Single Supply
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 16-SSOP (0.150", 3.90mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

APPLICATIO S I FOR ATIO
LTC2435/LTC2435-1
26
V
V
I
V
V
I
REF
REF
I
I
REF
REF
IN
IN
IN
IN
+
+
–
–
+
+
–
–
Figure 16. +FS Error vs R
V
V
CC
CC
V
V
I
I
I
I
LEAK
LEAK
LEAK
LEAK
CC
CC
–100
–10
–20
–30
–40
–50
–60
–70
–80
–90
10
0
I
I
I
I
LEAK
LEAK
LEAK
LEAK
1
V
V
V
V
V
F
T
O
A
CC
REF
REF
IN
IN
U
= GND
= 25°C
+
–
= 5V
R
R
R
R
+
–
= 3.75V
= 1.25V
SW
SW
SW
SW
= 5V
= GND
10
20k
20k
20k
20k
(TYP)
(TYP)
(TYP)
(TYP)
U
C
C
IN
SOURCE
IN
100
R
= 0.01μF
C
SOURCE
= 0.001μF
IN
C
IN
= 100pF
Figure 14. LTC2435/LTC2435-1 Equivalent Analog Input Circuit
= 0pF
1000
at IN
(W)
SWITCHING FREQUENCY
f
(F
f
(F
f
SW
SW
SW
O
O
W
= LOW OR HIGH)
= LOW)
= 76800Hz INTERNAL
= 69900Hz INTERNAL
= 0.5 • f
V
V
+
INCM
INCM
OSCILLATOR (LTC2435)
OSCILLATOR (LTC2435-1)
10000
or IN
C
18pF
(TYP)
EQ
+ 0.5V
– 0.5V
EOSC
Figure 15. An RC Network at IN
–
2435 F16
100000
(Small C
EXTERNAL OSCILLATOR
IN
IN
U
R
R
SOURCE
SOURCE
IN
)
2435 F18
C
C
IN
IN
Figure 17. –FS Error vs R
C
≅ 20pF
C
≅ 20pF
I IN
I IN
I REF
I REF
where
V
V
V
V
(
R
R
R
R
( )
( )
(
IN
INCM
PAR
PAR
REF
REFCM
EQ
EQ
EQ
EQ
+
+
−
=
= 43.2MΩ INTERNAL OSCILLATOR 60Hz NOTCH (F
= 52MΩ INTERNAL OSCILLATOR 50Hz NOTCH (F
= 48MΩ INTERNAL OSCILLATOR 50Hz/60Hz NOTCH (F
= (6.7 • 10
and IN
=
+
−
IN
AVG
AVG
: :
=
)
)
REF
AVG
=
+
AVG
⎛
⎜
⎝
100
–10
−
IN
⎛
⎜
⎝
=
=
90
80
70
60
50
40
30
20
10
IN
IN
LTC2435-1
+
REF
IN
0
LTC2435/
=
+
V
=
−
IN
−
+
–
–
1
V
−
−
1 5
2
12
−
IN
REF
.
+
+
IN
V
V
V
V
V
F
T
1 5
)/f
O
A
CC
REF
REF
IN
IN
.
+
+
2
V
•
2435 F19
0 5
−
EOSC
INCM
= GND
= 25°C
+
–
0 5
V
−
REF
.
V
•
⎞
⎟
⎠
= 5V
REF
+
–
INCM
.
= 1.25V
= 3.75V
V
•
REF
= 5V
= GND
10
•
R
0 5
−
EXTERNAL OSCILLATOR
−
R
−
EQ
0 5
.
⎞
⎟
⎠
EQ
.
V
−
−
V
REFCM
INCM
•
V
V
•
R
REFCM
C
INCM
R
EQ
IN
EQ
100
R
SOURCE
C
+
SOURCE
IN
= 0.001μF
+
V
C
= 100pF
REFCM
V
IN
C
REFCM
IN
= 0.01μF
= 0pF
1000
(W)
at IN
−
+
V
REF
V
REF
+
V
10000
IN
O
•
2
or IN
V
O
R
= HIGH) LTC2435
IN
•
2
EQ
= LOW) LTC2435
R
EQ
O
2435 F17
= LOW) LTC2435-1
–
100000
(Small C
IN
24351fb
)